STRESS THALLIUM IMAGING

Over the last 15 years, exercise thallium imaging has been the mainstay in noninvasive evaluation of patients with suspected or known coronary artery disease. With advancement in computer electronics involving image acquisition, storage, manipulation, processing and display, it is possible to increase the sensitivity and accuracy of the study. Further advancement in technology has been the introduction of rotational single photon emission computer tomography (SPECT) imaging. Due to lack of superimposition and overlap problems, perfusion abnormality is better evaluated in terms of site, extent and severity. Three-dimensional representation makes the quantitation of normal and abnormal myocardium possible, which is important to evaluate interventions either medical or surgical and risk stratification. We may have reached the peak of the camera technology, SPECT at least, and may need to look into better myocardial perfusion imaging agents with favorable physical characteristics, ready availability and simultaneous assessment of perfusion and function. 99(m)Tc may be one such agent. Thallium imaging for now remains the procedure of choice for myocardial perfusion imaging.